BACKGROUND AND PURPOSE: Sagittal craniosynostosis (SCS) is common and easily recognized and corrected surgically. However, rare cases of SCS are more complex: these associate closure of the metopic or delayed closure of the coronal suture, uni- or bilaterally.MATERIAL AND METHODS: We reviewed the available literature on atypical sagittal craniosynostosis (ASCS). We also reviewed retrospectively our series of SCS treated since 1980 and selected cases with simultaneous closure of the metopic (leptocephaly) or delayed closure of other sutures (plagiocephaly, oxycephaly, or Crouzon syndrome).RESULTS: ASCS is rare, representing <10 % of SCS. In our series, among 447 cases of SCS followed for a mean duration of 63.7 months, we identified 22 cases of ASCS: 6 with leptocephaly, 9 with non-syndromic oxycephaly, 4 with Crouzon syndrome, and 3 with plagiocephaly. Fourteen patients required a second operation, either planned initially (severe leptocephaly) or because of brain compression. The actuarial incidence of ASCS requiring reoperation was 5.3 % of SCS at 10 years. After a mean follow-up of 113 months, morphological results in ASCS were grade 1 (no defect) in 5, grade 2 (mild defect) in 2, grade 3 (minor reoperation) in 3, and grade 4 (major reoperation) in 12; one patient had visual impairment, and two had learning difficulties.CONCLUSIONS: ACSC can be detected initially or occur with a delay in apparently standard SCS. Leptocephaly is a specific entity. Because of the implications on the management and risk for the patient, preoperative evaluation of patients with SCS with CT scanner and prolonged follow-up are necessary.